First, i don't care much about GA matchmaking a lot, even if i am a player from the start with over a year break and (of course) a lot of crap and mistakes within my roster. I won a few GAs with weaker toons, and never really got last place so it is ok for me like it is actually.
But i can also understand why some players, especially the ones with an old unwiped account, want some more balance to the force ;-)
It takes a loooong time to build and develop, and you can't undone all of your mistakes you did because you din't knew what was coming, and how it will affect your gameplay. You cannot wipe toons that do not help you anymore to decrease your power. You can't deactivate abilities, units, etc.
The only thing you CAN do atm is to remove all of your mods from unused and unwanted toons. But that is just a drop in a bucket.
So one alternative to be competitive again (at least for GA), is to start a whole new account. Honestly i would not invest that much time again and would rather quit 'cause my patience isn't that great to do all these grinds again over the years (i am f2p). I like SW but i also like my time with family and friends, and to manage two accounts at same time or start a new one and abandon my old is out of the question (for me!).
Finally i chose option no. 3, to accept what i can't change, and make the best out of it. Obviously i decided to change my playstyle, don't level and gear every toon up, or activate it if not needed. Just the things i CAN do in my situation. I know that will be also a long way to come close to the ones with a second/third/whatever account without mistakes but it helps me to be more competitive over time.